The invention relates generally to magnetic recording, and, in particular, it relates to wave-shaping of drive currents for magnetic recording.
Magnetic recording on tape and similar media is a well developed and important technology. Of particular interest is digital, or more precisely binary, storage in which the magnetic tape is magnetized in one direction for one state and in another direction for another state. An example of a recorded magnetic tape is shown in the pictorial illustration of FIG. 1 in which the tape is divided into multiple sections, each a bit length long although the location of bit boundaries is arbitrary. A magentic recording head impresses a magnetization in either one direction or another, dependent on the data signal. The signal thus recorded is subsequently read by a read head using techniques well known in the art.
Tape systems have been developed which write multiple parallel channels or tracks on a single tape. These systems not only increase the bit density on tape but afford the simplicity in computer systems of simultaneously writing entire bytes or words without the need for serializing data available in parallel format.
Thin-film magnetic recording heads have been developed which allow the simultaneous fabrication of a multi-element head using fabrication techniques similar to those used in microelectronics. One such thin-film head is described by Raemaekers in a technical article entitled "Recording Experiments with Multi-Track Thin-film Heads", appearing in IEEE Transactions on Magnetism, vol. MAG-18, 1982, pp. 1143-1145.
A problem occurs with thin-film heads in that they are so lightweight that the head cannot adequately dissipate heat if all the elements in the head are simultaneously and continuously driven. This overheating problem could be solved by increasing the mass of the thin-film head. However, one advantage of thin-film heads is their small size and light weight, and that advantage would be negated by this solution. Alternatively, auxiliary cooling could be attached to the heads. This solution however also increases the head weight and further complicates its otherwise simple structure.